Computed tomography of thyroid carcinoma with intrathoracic extension

Eight cases of the thyroid carcinoma with intrathoracic extension were evaluated by CT. They consisted of 4 primary, and 2 recurrent thyroid carcinoma after palliative operation and another 2 mediastinal lymph nodes metastases after total thyroidectomy. Invasion to the trachea was correctly diagnosed in 5 of 6 cases. There were one false positive and one false negative case. The false negative case showed smooth compression deformity of the trachea by solid recurrent tumor. And the false positive case was a metastatic mediastinal lymph nodes which contained large cystic change and showed marked compression of the trachea. Involvement of large vessels, including the common carotid artery, internal jugular vein and innominate vein, were correctly diagnosed in all 5 cases. One recurrent tumor had esophageal invasion by thyroid carcinoma which could not be diagnosed preoperatively. The air filled esophagus did not show any deformity. (author)